JP2818766B2 - Defect inspection device for recording media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus for a recording medium, and is applied to an inspection system for a recording medium such as a magnetic disk or an optical disk. And a device that can easily make a pass / fail decision without knowing the details.

[0002]

2. Description of the Related Art Conventionally, when a defect inspection of a recording medium such as a floppy disk (FD) is performed by an inspection device, format data for inspection is written on the recording medium,
The above format data is read from the recording medium and reproduced, and the pass / fail judgment of the recording medium is performed by judging whether the written format data matches the read data.

In this case, a dedicated processor managed by the host is mounted on the inspection apparatus, and the processor executes R / W control of the magnetic recording / reproducing unit. In particular, in the read mode, the dedicated processor sequentially issues a read command corresponding to the sector designation data from the host side to the R / W.
The data is transmitted to the control unit, and the data of each sector read by the magnetic recording / reproducing unit are compared with the data of each written sector to determine whether or not they match.

In the data check for each sector, a method of comparing all bits and a CRC (Cyclic Redundancy Check) are used for writing data to each sector.
k) Add data and CRC for read data
And a method in which these methods are used in combination. In either case, the host side reads data for transmitting the sector designation data to the dedicated processor. It is necessary to set up a program for use. That is, information on the number, length, and position of each sector is incorporated in the host-side read program in advance,
At the stage when the read mode is set, the sectors are sequentially specified while synchronizing with the read timing.

[0005]

By the way, in the above-mentioned prior art, it is necessary to provide a readout program on the host side in advance, but the program has learned in detail the contents of the format data to be written. It has to be created above, and the work becomes very complicated. In the read mode, the host side sends sector designation data while taking the timing of reading out. However, since the host side also performs totalization of pass / fail judgment data, display / recording control, and the like, data processing is not performed. In some cases, the burden increases and the processing speed of other tasks is hindered.
Furthermore, the dedicated processors used are very expensive, which is a major factor in increasing the cost of inspection equipment.
You.

On the other hand, in a normal defect inspection of a recording medium, it is often sufficient to be able to judge normal / abnormal on a track basis, and it is not necessary to detect a defect on a sector basis. Therefore, the present invention provides an inspection apparatus for a recording medium that enables normal / abnormal judgment on a track-by-track basis with a simple circuit without preparing a read program on the host side. It was created for the purpose of eliminating points.

[0007]

SUMMARY OF THE INVENTION The present invention records / reproduces the format data to the recording medium to be inspected, the inspection device for a recording medium for defect inspection by detecting the error of the reproduced data, a recording medium Header and
Integer number of bytes composed of text data and CRC code
Writing means for sequentially writing format data of
When the read mode for write data is set,
Reading the format data sequentially from the recording medium
Output means and the data read by the read means.
Header detection means for detecting the header of the format data
Every time the header detection means detects the header.
Counts the number of bytes of format data including the header of
The byte counting means for counting and the header detecting means.
Each time the header is detected, the format
CRC means for performing a CRC on the packet data;
Record the total number of bytes that the format data can take.
Storage means and the count of the byte counting means
Compare the value with the number of bytes stored in the storage means
Comparison means, and a point in time when the comparison means obtains a comparison result of coincidence
The execution result of the CRC is detected, and the CRC
Count the number of executions without error
Normal number counting means for each track of the recording medium.
The count number of the normal number counting means and its track
Acceptance by comparing the number of the format data that has been written
And a pass / fail judgment means for making a judgment.
The present invention relates to a recording medium defect inspection apparatus .

[0008]

According to the present invention, format data of an integer number of bytes consisting of a header, text data and a CRC code is written to a recording medium, and at the read stage, the start of each format data is confirmed by detecting the header, and based on the detection, Then, the counting of the number of bytes of the read data is started and the execution of the CRC for the read data is started.

Here, the start of each format data is confirmed by the detection of the header. However, since the format data has various data lengths depending on the length of the text data, the reading completion time of each format data is uniform. Cannot be detected by any means. Therefore,
The number of bytes of the read data is counted based on the detection of the header, and when the count value matches one of the total number of bytes that can be taken by the format data stored in the storage means in advance, reading of one format data is completed. Detect as a time point candidate.

Accordingly, the above-mentioned candidate at the time of completion of reading is detected a plurality of times during the reading of format data having a long data length. However, if there is no error in the read format data, the format data is always read. At the completion time, the execution result of the CRC is determined as “no error (residue result matches the CRC code)”, and at the timing of the candidate for the read completion time detected up to that time, the remainder as the execution result of the CRC is CRC. Does not match sign. That is, every time a candidate at the time of completion of the reading is detected, a CRC execution result for the read data is detected, and 1
By counting the number of times that the CRC execution result for each format data is "no error" in the track reading process, if no error exists in the track, the count value (P) is written to the track. This will be the same as the number (Q) of format data included.

In the present invention, the count value (P) and the number of format data (Q) are sequentially compared for the tracks of the recording medium based on the above principle, and P = Q is satisfied for all the tracks. If it is satisfied, it is determined to be a pass product, otherwise, it is determined to be a reject product.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows a block circuit diagram of a disk inspection system, where 1 is an inspection unit, and 2 is a personal computer (personal computer) on the host side. In the figure,
The inspection unit 1 includes a magnetic recording / reproducing unit 3 that performs R / W on a disk to be inspected, an R / W control unit 4 that controls the R / W operation, ROM5 storing data for use (format data), and a magnetic recording / reproducing unit
3 includes an amplifier 6 for amplifying the reproduced signal, an A / D converter 7 for quantizing the signal amplified by the amplifier 6, and a power supply unit 8 for supplying power to the entire inspection unit 1. As a circuit element according to the embodiment, a header detector 9 for detecting a header from an RD signal (read data) output from the A / D converter 7 and the number of bytes of the read data based on the detection signal of the header detector 9 And a C counter for the read data based on the detection signal of the header detector 9.
A CRC operation unit 11 that executes RC and outputs an “H” pulse when the remainder result matches the CRC code, and a data length (byte number data) that the format data can take
And a comparator 13 which compares the count value of the byte counter 10 with the byte number data of the ROM 12 and outputs an "H" pulse when the comparison result becomes the same.
And the output of the CRC operation unit 11 and the output of the comparator 13 in positive logic
It is characterized in that it has an AND circuit 14 for ANDing and a normal number counter 15 for counting the output pulses of the AND circuit 14. The header detector 9 and the CRC calculator 11 are synchronized by the RC signal output from the R / W controller 4.

On the other hand, the personal computer 2 on the host side has an R / W control unit.
A control signal is supplied to the power supply unit 4 and the power supply unit 8, and the count value of the normal number counter 15 is fetched to make a pass / fail judgment of the disk, and the read data obtained from the A / D converter 7 is also fetched and saved. It has become.

Next, a procedure of inspecting a disk by the system of the embodiment will be described with reference to FIGS. First, when the disk 16 to be inspected is set in the magnetic recording / reproducing unit 3 of the inspection unit 1, the write mode is set, the R / W control unit 4 reads the format data for inspection from the ROM 5, and writes the data to the magnetic disk. Transfer to the recording / playback unit 3 and disc 1
Write to 6. As shown in FIG. 2, the format data includes a 1-byte header, an integer number of bytes of text data, and a 2-byte CRC code. The length of the text data is 4 bytes, 128 bytes, 256 bytes, and 512 bytes.
1024 bytes,..., Etc., and as a whole N bytes (N = 7, 131, 259, 515, 102
7,...). Where the data length is
The above setting is based on the following reason.
Generally, one sector of a magnetic disk includes an ID field.
Data composed of data fields is written and ID
The field is a 1-byte header and 4-byte text
Data and a 2-byte CRC code.
The field consists of a 1-byte header and 128 bytes, 25
6-byte, 512-byte, 1024-byte, ... minute text
Data and a 2-byte CRC code.
Therefore, the ID field and the data field are
The only difference is the data length of the text data part.
Fields have a similar format.
At a glance, the above format data can be used for simulated inspection.
It can be used as data by a magnetic recording / reproducing device.
This corresponds to the state of recording / reproducing on the disk.

Next, when the writing is completed, the mode shifts to the reading mode, and the magnetic recording / reproducing unit 3 sequentially reads the format data written on the disk 16. Then, in this read mode, the header detection unit 9, the byte counter 10, the CRC operation unit 11, and the comparator 13 operate according to the procedure shown in the flowchart of FIG. First, the read data is output from the A / D converter 7 by reading the format data. When the header of the format data is detected by the header detector 9, the CRC calculator 11
Is reset, and the CRC operation unit 11 starts execution of the CRC using a given generator polynomial (S1, S2, S
3). Then, the CRC calculation unit 11 is reset every time a header is detected, and executes a CRC for each format data read sequentially (S9 → S2).

On the other hand, the byte counter 10 is also reset by the header detection of the header detector 9 and the byte counter 10 is reset.
Starts counting the number of bits of read data output from the A / D converter 7, and when one byte of data is detected, increments the count value by +1 and compares the count data of that byte number with the comparator. 13 (S1,
S3, S4, S5). Here, the comparator 13 compares the count data of the byte counter 10 with each byte number data stored in the ROM 12, and when those data do not match, the output is set to “L”. As soon as they match, an "H" pulse is output (S6, S7, S8). Then, the byte counter 10 and the comparator 13 repeat the operation until the next header is detected (S9 → S4).

In the above procedure, the ROM 12
Stores byte number data relating to all data lengths that can be taken by the format data, and the value thereof corresponds to the above N bytes (N = 7, 131, 259, 515, 1027,...). Therefore, the comparator 13 outputs an "H" pulse every time the read data reaches the number of bytes. That is, the format data has various data lengths depending on the length of the text data, which corresponds to any of the number of bytes specified by N, and the comparator 13 determines when the reading of the single format data is completed. "H"
This is indicated by the pulse output timing.

The CRC calculation unit 11 repeatedly executes the CRC calculation based on the detection of the header (S1, S2, S3,
(S9 → S2) When all the format data corresponding to the header is read, the result of the remainder operation is compared with the added CRC code, and if they match, an “H” pulse is output as an error-free detection signal. . Therefore, if there is no error in the read format data, CR
The timing of the "H" pulse output from the C operation unit 11 and the timing of the "H" pulse output by the comparator 13 should match, and as a result, the AND circuit 14 outputs the "H" pulse. That is, even if one read format data has various data lengths specified by N, if there is no error in the read format data (the write area of the format data of the disk 16). At the completion of the read, A
The ND circuit 14 outputs one "H" pulse.

The normal number counter 15 is an AND circuit 14
Every time the “H” pulse is output, the count value is incremented by +1.
Then, the number of cases where no defect exists in the write area of the format data is counted.

In the system of this embodiment, the pass / fail judgment of the disk 16 is performed in track units, and the judgment procedure is shown in the flowcharts of FIGS. First, an index hole is formed in the disk 16, and the magnetic recording / reproducing unit 3
When an index hole is detected, an index pulse is output to the normal number counter 15. Then, the normal number counter 15 is reset by the index pulse.
(S21 → S22, S25, S26 → S22), and based on the procedure shown in the flowchart of FIG. 3, every time both the CRC operation unit 11 and the comparator 13 simultaneously output an “H” pulse, the AND circuit 14
The count value is incremented by +1 according to the pulse output (S23, S24).

Therefore, by checking the value of the count value of the normal number counter 15 between the preceding and succeeding index pulses, it is possible to determine whether or not there is a defect in the track being read during that time. That is, the number (Q) of format data written to each track of the disk 16 is known, and if there is no defect in the track, the number (Q) is
(Q) should match the count value (P) of the normal number counter 15.

Therefore, the host-side personal computer 2 reads the count value (P) of the normal number counter 15 immediately before resetting each time an index pulse is detected (S26), and FIG.
The count value as shown in the flowchart of
(P) is compared with the number (Q) of format data stored in advance as an expected value (S27).

As a result of the comparison, if P = Q, it is determined that the track has no defect,
Conversely, if P ≠ Q, it is determined that the track has a defect (S28, S29). In the system of this embodiment, the above procedure is repeated to perform a defect inspection for each track of the disk 16. If P ≠ Q and it is determined that a track has a defect, the defect is immediately checked. The disk 16 may be processed as a defective product, and the process may proceed to the inspection of the next disk.

[0024]

The recording medium defect inspection apparatus according to the present invention has the following effects by having the above configuration. Track defects can be automatically detected without providing a read program for inspection format data written on the recording medium on the host side, eliminating the need to spend time and effort on program creation, and the contents of the inspection format data. Can be detected without knowing the details of the inspection system, so that an operator who does not have advanced knowledge of the inspection system can easily operate the inspection system and easily recognize the inspection result. On the other hand, on the host side, it is not necessary to transfer the sector-specific data one by one to the inspection unit as in the related art, and it is sufficient to read the count number obtained by the inspection unit every time reading of each track is completed. The burden on data transfer and processing is reduced, and other tasks can be executed with a margin. Furthermore,
The apparatus of the present invention can execute the procedure with a simple circuit configuration combining general-purpose units, and it is not necessary to use an expensive dedicated processor for read control as in the related art. It also has the advantage of reducing power consumption.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of a disk inspection system according to an embodiment.

FIG. 2 is a diagram illustrating a configuration of inspection format data.

FIG. 3 is a flowchart illustrating an operation procedure of a header detection unit, a byte counter, a CRC calculation unit, and a comparator in a read mode.

FIG. 4 is a flowchart showing a defect inspection procedure in track units.

FIG. 5 is a flowchart showing a defect determination procedure in track units on the host side.

[Explanation of symbols]

Reference Signs List 1 inspection unit 2 personal computer (host) 3 magnetic recording / reproducing unit 4 R / W control unit 5 ROM (storage of write format data) 6 amplifier 7 A / D converter 8 power supply unit 9 header detection unit 10 byte counter 11 CRC Arithmetic unit 12 ROM (byte number data of format data) 13 comparator 14 AND circuit 15 normal number counter 16 disk

Claims (1)

(57) [Claims] 1. A recording medium inspection apparatus for recording / reproducing format data on a recording medium to be inspected and performing a defect inspection by detecting an error in the reproduced data . Header, text data and CRC
(Cyclic Redundancy Check)
Writing means for sequentially writing the number of format data,
When the read mode related to the write data is set
Then, the format data is sequentially read from the recording medium.
Reading means for outputting, and whether the data is read by the reading means.
Header detection for detecting the header of the format data from the
Output means, and the header detection means detects the header
The number of bytes of format data including the header each time
Counting means for counting the number of bytes, and detecting the header
Each time the means detects the header, a file containing that header is included.
CRC hand to execute CRC on format data
Column and all bytes that the format data can take
Storage means for storing the number, and
The count value is compared with the number of bytes stored in the storage means.
Comparing means for comparing, and the comparing means obtains a comparison result of coincidence.
The execution result of the CRC at the time when the
Count the number of RC execution results without error
Means for counting the number of normal times, and tracking of the recording medium.
Count of the normal number counting means and its
Compare the number of format data written to the
And a pass / fail determination means for performing pass / fail determination by using
Inspection device for recording media .